Clamping or compressing apparatus



May 13, 1941. J. 5. STULL CLAMPING OR COMPRESSING APPARATUS Filed April16, 1938 V 5 RN m w m N 7 W5 5% w. 2 W

0 m an. a O 4 v. G mum" f0 5 2 Patented May 13, 1941 UNITED STATES IPATENT OFFlfiE John S. Stull, Chicago, Ill., alaignor to WesternElectric Company, Incorp ra ed, New York. N. Y., a corporation of NewYork Application April 1a, 1931;, Serial No. 202,580

3 Claims. CL 121-38) ducting contact springs and insulators i2 and II,

This invention relates to clamping or compressing apparatus, andparticularly to a control for such apparatus whereby articles may besub- -jectjed to a predetermined uniform pressure.

Contact spring assemblies or pile-ups of relays used intelephoneequipment are usually manufactured from a plurality of alternatelyarranged conducting contact springs and insulators with end platesclamped or compressed together uniformly. These pile-ups vary inthickness before clamping or compressing and it is difiicult to clamporcompress them uniformly. j I

The'object of this invention is to overcome this objectionable featurein clamping or compressing articles such as contact spring pile-ups andto provide a quick and efficient control mechanism for clamping orcompressing apparatus which will automatically apply a predetermineduniform clamping or compressing pressure to articles of varyingvdegreesof thickness.

In attaining this object, a pairof relatively movable clamping orcompressing heads are operated by a fluid pressure piston through apredeterminedly compressed spring operating the heads, Upon the springbeing further compressed in the operation of the piston a predeterminedamount which will provide the desired pressure to the article, meanscontrolled by the spring interrupts the supply of pressure fiuid to thepiston and no further compression of the article occurs, so that theaggregate pressure applied is determined by the spring and does not varywith the thickness of the articles.

Other objects and advantages of the invention will be understood byreference to the following specification and accompanying drawing, inwhich Fig. 1 is a side-view partly in section of a compressingiapparatusembodying the control mechanism of this invention with a relay contactspring pile-up, shown in section, ready to be compressed, and

Fig. 2 is a fragmentary plan view of Fig. 1.

Referring to the drawingwherein one embodimerit of the invention isshown applied to a bench type compressing apparatus Iii which isapplicable to clamping or compressing spring contact assemblies, orpile-ups ll, of electrical relays to a predetermined amount so that allassemblies of the same kind within the capacity of the apparatus may besubjected to a similar clamping, compressing and holding pressure,irrespective of. slight variations in the height of such assemblies.Such spring pile-ups generally comprise a plurality of alternatelyarranged conrespectively, and end plates i4. Variations in the height ofthis type of assemblies are due to difficulties in maintaining desireddimensional tolerances in the thicknesses of the various elementscomprising the pile-ups in commercial manufacturing practice.

' The spring pile-up Ii may be loosely assembled on a support I'I priorto being mounted, as shown in the drawing, on the apparatus I! withretain-. ing screws l8 extending through aligned apertures in theelements of the pile-up, the support being provided with depressions forreceiving the projecting ends of the screws. The support I! serves as astationary clamping head which is moved into clamping position upon aplate I9 fixed in a stationary bench top 20, the plate having rails 2|and a stop member 22 (Fig. 2) for guiding and stopping the support incorrect posi- 20." An arm 21 extends from the movable head 24 over thesupport i1 and is providedwith a pair of vertically extending apertures28 dimensioned to freely receive theheads of the retaining screws iii ofthe pile-up II. The lower surface of the head arm 21 is formed with acontinuous channel 29 interconnecting the apertures 28 and permittingthe movement of the pile-up H on the support I! into the position shown.

The head 24 is moved downwardly to compress the spring pile-up il apredetermined amount by the actuation of a fiuid pressure or)- eratedpiston 3| carried in a cylinder 32 which is pivoted at 33 to the lowersurface of the bench top 20. J i

To interconnect the head 24 and the piston 3| and serving to control thesupply of fiuid pressure to the underside of the piston upon the springpile-up Ii being subjected to the desired pressure the followingmechanism is provided.

Pivoted at 34 to the lower end of a piston rod 35 attached to the pistonSi is a lever 38 fulcrumed at, to a vertical standard 40 integral with abase plate 4| which is fixed to the floor. A short distance from itsfulcrum ,point 31 the lever 28, is pivoted at "to the lower end of a rod42 which extends'into a tubular spring housing 45, the rod having fixedtoits upper end a collar 46 slidably fitted in the housing.- Screwthreaded into the lower end the housing 4| is an adjustable collar 41through which the rod 43 is freely slid'able. Within the housing 4|,surrounding the rod 48 and abutting at opposite ends opp sed surfaces ofthe collars 4| and 41 is a coiled compression spring 4|, which isinitially compressed a predetermined amount substantially correspondingto but slightly less than the desired pressure to which the pile-up iiis to be subjected. by the adjustable collar 41. At its upper end thespring housing 45 is pivotally connectedat ID to the clamping head 24which is extended at its lower end freely through an aperture in theplate II and bench top 2|.

In the normal position of the clamping head I4, as shown, the collar 4'abuts the inner end wall of the housing 45 and the piston Ii is at thebottom of its stroke abutting an inner collar II on the lower head ofthe cylinder 82.

A forked arm 52 welded to the spring housing 4i depends below the lowerend of the housing and extending through the furcations of the arm is ahorizontal arm II fixed to the rod 43. the free end of the arm I!carrying an adjustable screw 64, the purpose of which will be made clearpresently. Fixed to the arm 52 is a valve housing Bl having an outletport 58 connected to the cylinder 32 below the piston Si by means of aflexible conduit 50 and an inlet port 40 connected to a manuallyactuated two-way control valve of any suitable conventional type,indicated in general at 6|, by means of flexible and rigid conduits U2.The cylinder 22 above the piston 3| is connected to the valve 8| bymeans oi flexible and rigid conduits 03. A suitable source (not shown)of fluid pressure is connected to the valve I by a conduit Cl and anexhaust conduit for the valve is indicated at 61. The control valve I isequipped with an actuator or foot treadle II for controllingthedirection of the fluid pressure therefrom. In the normal position ofthe movable clamping head 24, as shown, the treadle i8 is held in araised position, as shown in full lines, against a stop screw '8 by theaction of a coiled compression spring Ill and'the fluid pressure isbeing directed therefrom through the conduits II to the cylinder 32above the piston 3 i, thus maintaining the latter in the normalposition, as shown. A stop member 12 on the treadle 00 engaging the baseplate 4| limits the movement of the treadle 68 to its depressedposition, indicated in dotted outline.

A valve 13 in the valve housing 55 is provided with a depending stem 14which extends throughthe housing and is centrally aligned with theadjustable screw 54 movable with the rod 43, which is operativelyassociated with the compression spring 48. In the normal position of theclamping head 24, as shown, the valve is held in a raised or openposition by the previously adjusted screw 54, which is being urgedupwardly by the action of the compressed spring 48. The valve 13, whenthe screw 54 recedes from the valve housing at the completion of thecompressing operation, is moved to a closed position by the energystored in a coiled spring 15, which is held compressed in the normalposition of the clamping head 24 by the screw abutting the valve stem14.

A description of the operation of the apparatus in to clamp under adesired uniform pressure the same type of spring contact assemblies orpileups Ii irrespective of slight variations in the height of suchassemblies and holding the pressure while the retaining screws it aretightened is as follows:

. mined amount,

Assumingthepartsareintheirnormalposition, as described with the spring44 under a predetermined initial compression slightly less than that towhich the assembly is to be subjected, the pile-up ll previously looselyassembled upon the support i1 is slid by an operator into position onthe bench plate ll between the guide rails 2i and against the stopmember 22 and thus is correctly aligned under the arm 21 of the movablehead 24 and slightly spaced therefrom, the heads of the screws ll beingcentered with the apertures 28 in the head arm. The operator nowdepresses the foot treadle II and the fluid pressure is supplied to thecylinder 32 below the piston 3| through the conduits 02 past the openvalve 18 and conduit II and the piston moves upwardly, the fluidpressure at the opposite side of the piston escaping by means of theconduits ll, valve ll and exhaust conduit 81 to atmosphere.

'me upward movement of the piston Ii through the piston rod SI and leverll first moves the rod 43 carrying the collar 40 downwardly whichmovement is likewise transmitted to the housing 48 through the spring 48and collar 41. As the housing moves downwardly, the clamping head 24connected thereto also moves down and the space between the arm 21 ofthe head and the pile-up II is closed up. Up to this point, in theupward movement of the piston 8 l no appreciable change from the initialcompression in the spring 40 has occurred. In the continued upwardmovement of the piston ii, the rod 43 continues to move downwardly andpull on the spring 4! and the pile-up is compressed to an amount wherethe resistance of the spring is overcome. The point at which the spring4! yields, which corresponds to the desired pressure to which thepile-up II is to be subjected, results in the downward movement of thecasing 4| being halted and in the compression thereafter of the spring44 the screw 44 carried by the rod 43 receding from the housing llpermits the valve stem 14 to follow under the action of the valve springI! and the valve I3 is moved to its closed position and the supply offluid pressure to the underside of the piston II is thus automaticallyinterrupted upon the assembly being compressed a predeterwhich iseflected instantaneously upon depressing the treadle 84. The operator,while still holding the treadle 88 depressed, inserts a screw driverblade (not shown), which may be preferably power driven, successivelyinto the apertures 28 of the clamping head 24 to operatively engage theheads of the retaining screws i8 and the screws are drawn tight to holdthe compression on the pile-up II.

The operator thereafter takes the pressure of his foot ofl the treadle40 and it returns to its normal position, whereupon the fluid pressureis directed through the conduits I to the cylinder 32 and above thepiston 2|, which thereupon moves downwardly to its normal position. Thespring 48 is thus permitted to expand, which causes the spring housing45 and the clamping head 24 to move upwardly to the normal positionthereof and likewise the screw 54 moves the valve 13 to its openposition, the parts all now being in their normal position, as shown,and upon withdrawing the support I! with the compressed pile-up II fromunder the head 24, the apparatus is ready to receive another pile-up Iifor a similar amount of compression irrespective of slight variations inthe heights thereof.

From the above description of one embodiment of this invention it isapparent that a very simple and efllcient control mechanism forcompressing apparatus is provided, whereby similar type articles orassemblies of elements may be subjected to a predetermined uniformpressure irrespective of slight variations in the height thereof and thepressure maintained while work is performed on the compressed article.

Although only one specific embodiment and application of the inventionhas been shown and described herein, it should be understood that thecontrol mechanism is capable of other modifications and adaptationswithout departing from the spirit and scope of the appended claims.

What is claimed is:

1. A control mechanism for compressing apparatus having movable andstationary pressure elements comprising a source of fluid underpressure, a piston actuated by said fluid, a direct mechanicalconnection between the piston and movable pressure element including atubular member connected to the movable pressure element, a shoulderedmember reciprocable in the tubular member, an element adjustable in thetubular member, a predeterminedly tensioned means interposed between theshouldered member and said adjustable element through which motion isapplied to the movable pressure element to apply pressure apredetermined amount and thereafter to yield, and means associated withsaid shouldered and tubular members responsive to the yielding of saidtensioned means a predetermined amount to control the movement of saidpiston.

2. A control mechanism for compressing apparatus having movable andstationary pressure elements comprising a source of fluid under pres..sure, a piston actuated by said fluidja direct mechanical connectionbetween the piston and movable pressure element including a tubularmember connected to the movable pressure element,

a shouldered member reciprocable in the tubular element, an elementadjustable in the tubular member, a compression spring predeterminedlycompressed between the shouldered member and said adjustable elementthrough. which motion applied to the movable pressure element to applypressure a predetermined amount and there after to yield, and constantlyengaged elements carried by said shouldered and tubular membersresponsive to the yielding of said spring a predetermined amount tocontrol the movement of said piston.

3. A control mechanism for compressing apparatus having movable andstationary pressure elements comprising a source of fluid underpressure, a piston actuated by said fluid, a rod connected to saidpiston, a direct mechanical connection between the piston rod andmovable pressure element including a tubular member pivotally connectedto the movable pressure element, a shouldered member reciprocable in thetubular member and extending therefrom at one end, an element adjustablelongitudinally in the tubular members, a pivotally supported linkpivotally connected at opposite ends to said piston rod and theextending end of said shouldered member, a predeterminedly tensionedspring interposed between the shouldered member and said adjustableelement through which motion is applied to the movable pressure elementto apply pressure a predetermined amount and thereafter to yield, meansincluding a valve carried by. said tubular member for supplying saidfluid to the piston, and means responsive to said tensioned springbefore it yields for maintaining the valve in fluid supplying positionand responsive to the yielding of the spring for interrupting the supplyof fluid to said piston.

J OHN S. STULL.

